Bacteriolysis

BACTERIOLYSIS, the dissolution of bacteria occurring in an immune organism with the participation of the latter's serum. Bacteriolysis was first demonstrated by R. Pfeiffer and Isaev in relation to cholera vibrios. If a loop (2 mg) of live, highly virulent cholera vibrios is injected into the abdomen of a guinea pig immunized against cholera, rapid destruction of the latter occurs in the peritoneal cavity. This is easy to verify if one extracts exudate from the peritoneal cavity using capillary (Pasteur) pipettes and studies the changes in the vibrios under a microscope. Almost instantly, they lose their motility, become oval, and then turn into round formations in the form of granules. These granules stain well at first, but then become paler and paler and, in the end, dissolve; this entire process lasts 15–20 minutes. This so-called Pfeiffer-Isaev "phenomenon" can also be obtained by introducing a mixture of anti-cholera immune serum and cholera vibrios into the peritoneal cavity of a non-immunized guinea pig. Bacteriolysis is a strictly specific process; therefore, it is used for differential diagnostic purposes. As an immunobiological process, bacteriolysis is significant, in addition to cholera, in typhoid fever, paratyphoid, and infections caused by Escherichia coli; bacteriolytic properties of sera have also been proven in spirochetal and trypanosomal diseases. According to Kraus and Hofer and others, an organism immune to tuberculosis possesses the ability to lyse tubercle bacilli; other researchers (Burnet, Calmette) dispute this. To determine the bacteriolytic capacity of serum, in addition to the Pfeiffer phenomenon, one can also use an in vitro experiment. An emulsion of the microbe (e.g., cholera vibrio) is prepared at a rate of 1 loop of culture per 1 cubic centimeter of broth. The test serum is diluted beforehand by 10, 100, and 1,000 times; then, fresh guinea pig serum (alexin) is taken in a dilution of 1:10. The experiment consists of mixing a drop of the bacterial emulsion with a drop of the various dilutions of the test serum, previously heated to 50°, and a drop of fresh serum (alexin). The mixtures are examined in a hanging drop, during which one observes the sequential agglutination of the microbes, their transformation into granules ("spheres"), and dissolution. Methods for the quantitative determination of the bacteriolytic power of serum have also been proposed by counting the colonies of the microbe that grew after preliminary treatment of its emulsion with the test serum, heated to 56°, in various dilutions of alexin (Bordet). Regarding the relationship of bacteriolysis to bacteriophagy, see Bacteriophagy. Bacteriolysins, according to Ehrlich's theory, are specific immune bodies (antibodies) participating in the process of bacteriolysis and having the character and properties of amboceptors. Bacteriolysins manifest their action only in the presence of complement (alexin); therefore, if serum possessing bacteriolytic properties (e.g., anti-cholera) is heated to 56° (15 minutes), it loses the ability to lyse bacteria, because heating destroys the complement (alexin); the addition of fresh serum containing complement to such inactivated serum restores its bacteriolytic ability. Normal serum also contains bacteriolysins against cholera vibrios, typhoid bacilli, and other microbes ("normal" bacteriolysins), which, however, act in low titers.